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Reactions of tetrathiotetraimide

Younger, D.

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REACTIONS OF TETRATHIOTETRAIPIIDE

by

D. Younger, B.Sc.

A t h e s i s submitted f o r the Degree of Master of Science i n the Un i v e r s i t y of Durham.

A p r i l 1970.

mm

( i )

ACKNOULEDGEPIENTS

The author wishes t o express h i s g r a t e f u l thanks t o Dr. A, 3,

Banister, under whose d i r e c t i o n t h i s research was c a r r i e d out, f o r

h i s valuable adv/ice and u n f a i l i n g encouragement; and t o the Senate

of the U n i v e r s i t y of Durham f o r research f a c i l i t i e s .

( i i )

nEnoRANDun

The uork described i n t h i s t h e s i s was c a r r i e d out i n the

U n i v e r s i t y of Durham between October 1967 and A p r i l 1970. This

work has not been submitted f o r any other degree and i s the o r i g i n a l

work of the author except where acknowledged by reference.

( i i i )

ABSTRACT

The aims of the work described i n t h i s t h e s i s are to study the reactions

of t e t r a t h i o t e t r a i m i d e and t o attempt t o systematise i t s chemistry. Tetra-

t h i o t e t r a i m i d e i s one of the series of sulphur imides S (NH)„ derived ^ 8-x

from octasulphur. The i n t r o d u c t i o n describes the reported chemistry of a l l

known imides derived from octasulphur up t o the time of w r i t i n g , and t h e i r

behaviour i s discussed i n terms of seven r e a c t i o n types.

( i ) A d dition reactions w i t h organic substrates

( i i ) Adduct formation w i t h Lewis acids

( i i i ) Hydrogen s u b s t i t u t i o n

( i v ) Hydrogen a b s t r a c t i o n

(v) Oxidation t o t h i o n y l i m i d e s

( v i ) Ring degradation

( v i i ) Ring c o n t r a c t i o n e.g. t o ^^^-^ ov (NSCl)^

The behaviour of t e t r a t h i o t e t r a i m i d e has been i n v e s t i g a t e d w i t h four

types of compoundsJ ( i ) metal halides (Lewis a c i d s ) ,

( i i ) other compounds containing r e a c t i v e halogen,

( i i i ) organometallic compounds, and .

( i v ) oxygen compounds ( a l l containing the group ^ ^ ) .

Two new 1:1 adducts of t e t r a t h i o t e t r a i m i d e w i t h AlBr^ and A l C l ^ are

described, these are probably o-adducts v i a donor n i t r o g e n .

(iw)

Ring c o n t r a c t i o n from the eight-membered (SN)^ r i n g to (a) the

SBuen-membered r i n g c a t i o n Ŝ '̂ 3̂ » (b) the six-membered (SN)^ ring-by

r e a c t i o n w i t h the halogens and several a c t i v e halogen compounds i s reported

f o r the f i r s t time.

F i n a l l y , the preparation of a t e t r a t h i o t e t r a i m i d o l i t h i u m d e r i v a t i v e ,

and i t s use as a possible r e a c t i o n route t o (SI\1X)^ d e r i v a t i v e s , i s d i s -

cussed.

(v)

CONTENTS

INTRODUCTION

Page

1. T E T R A T H I O T E T R A i n i D E (SNH)^

General p r o p e r t i e s 1 S t r u c t u r e 1 Preparation 1 Reactions 2

2. OTHER i n i D E S DERIUED FROM OCTASULPHUR

Preparation 13 Heptasulphur imide Ŝ NH 14 The hexasulphur diimides SgCNH)^ 14 The pentasulphur t r i i m i d e s Sg(NH)2 14 Structures 15' Reactions 16

EXPERiriENTAL Handling techniques 22 I n f r a r e d spectra 22 P u r i f i c a t i o n of solvents 22 Preparation of s t a r t i n g m a t e r i a l s 23

T e t r a t h i o t e t r a i m i d e 23 Manganese ( l l ) and I r o n ( l l ) c h l o r i d e s 24 Aluminium bromide 24 Aluminium c h l o r i d e 24 Tin tetrabromide 24 T r i m e t h y l c h l o r o s i l a n e , Acetyl c h l o r i d e and bromide 24 N-Bromodiphenylketimine 25 Hydrogen c h l o r i d e 25 Benzoyl and s u l p h u r y l c h l o r i d e s 25 Tetrachloroethylene 25 Methyl Iodide, lodobenzene and Acetic anhydride 25

( v i )

Paqe

Ethylene oxide and Epichlorohydrin 25 n-Butyl l i t h i u m 25

REACTIONS IMWESTIGATED

Section I . Pletal Halides

Manganese ( l l ) c h l o r i d e 27 Ir o n (11) c h l o r i d e 27 Aluminium bromide 27 Aluminium c h l o r i d e 28 Tin tetrabromide 28

Section I I . Other Halides

T r i m e t h y l c h l o r o s i l a n e 30 Acety l c h l o r i d e 31 Acety l bromide 32 Bromine 33 N-Bromosuccinimide 34 l\l-Bromodiphenylketimine 35 Benzoyl c h l o r i d e 37 Hydrogen c h l o r i d e 38 Chlorine 38 Sulphuryl c h l o r i d e 39 Tetrachloroethylene 39

Section I I I . Orqanometallics

Trimethylaluminium 40 n-Butyl l i t h i u m 40

Reactions between (SI\ILi)^ and; Methyl i o d i d e 41 Tr i m e t h y l c h l o r o s i l a n e 41 Acetyl bromide 42 lodobenzene 42 Chlorine 43

( v / i i )

Page

Section (m). Oxygen Compounds

Acetic anhydride 44 Ethylene oxide 44 Epichlorohydrin 45

DISCUSSION

Metal Halides 46

Other Halides

T r i m e t h y l c h l o r o s i l a n e 47 Ace t y l c h l o r i d e 47 Ace t y l bromide 49 Bromine 49 N-Bromosuccinimide 51 N-Bromodiphenylketimine 52 Benzoyl c h l o r i d e 54 Hydrogen c h l o r i d e 54 Chlorine 55 Sulphuryl c h l o r i d e 56 Tetrachloroathylene 57

Orqanometallics

Trimethylaluminium 58 n-Butyl l i t h i u m 58 T e t r a t h i o t e t r a i m i d o l i t h i u m 59

Oxygen Compounds

Acetic anhydride 61 Ethylene oxide 61 Epichlorohydrin 61

( v i i i )

Figures and Tables i n Text

Page

Fi g . 1. Structure of T e t r a t h i o t e t r a i m i d e 2 2. Reactions of (SNH)^ 12 3. Imides derived from Octasulphur 16 4. I n f r a r e d spectrum of (SNH)^ 26 5. I n f r a r e d spectra o f ; S^IM^Br/lMH^Br, NH^Br and S^N3Br 48

Table 1. A l k y l d e r i v a t i v e s of (SI\IH)^ 6 2. Reactions between (SNH)^ and RSO2CI 10 3. Acyl d e r i v a t i v e s of Sulphur Imides 17 4. A l k y l d e r i v a t i v e s of Sulphur Imides 19 5. Colours of Ŝ N̂ Ĥ anions 59

REFERENCES 62

- 1

1. TETRATHIOTETRAIMIDE

General Properties

T e t r a t h i o t e t r a i m i d e i s an a i r - s t a b l e , diamagnetic, colourless

c r y s t a l l i n e s o l i d melting p o i n t 152° ^, 145° ^, 156° ( t h i s work). I t 1 1 i s not wetted and not dissolved by water , i s r e a d i l y soluble i n p y r i d i n e

1 3 1 3 3 and THF ( t h i s work), and s l i g h t l y soluble i n acetone ' , e t h y l ' and amyl 3 3 3 a l c o h o l s , ether , carbon disulphide and p i p e r i d i n e .

S t r u c t u r e

The s t r u c t u r e has been determined by X-ray^'^ and neutron d i f f r a c t i o n ^

s t u d i e s . The molecule has a puckered ei g h t membered r i n g w ith a l t e r n a t e

S and N atoms, i d e n t i c a l SN bond lengths, and coplanar SNHS groupings, the

i . r . spectrum i n d i c a t e s NH r a t h e r than SH bonds (organic imides absorb at 1 —1 ^ c 3500-3220 cm" , t h i o l s i n 2600 cm region ) , The SN distance, 1.674 ± 0.004 f

9

i n d i c a t e s a bond order s l i g h t l y greater than one , even though the formal

bond order i s one. I t i s now generally accepted t h a t (SNH)^, i n common with

S^N^ and other r e l a t e d SN r i n g systems contains alT-delocalised system of

e l e c t r o n s ' ' ' ' ^ w h i c h may be thought of as being derived from iT overlap of

n i t r o g e n lone p a i r electrons and empty sulphur d o r b i t a l s .

The s t r u c t u r e of (SWH)^ i n the s o l i d s t a t e i s shown i n F i g . 1.^'^

Preparation The p r e f e r r e d preparative route i s by reduction of Ŝ N̂ i n benzene

12

s o l u t i o n by methanolic stannous c h l o r i d e , though reduction of Ŝ N̂ w i t h

d i t h i o n i t e has been reported (but without p r a c t i c a l details)''".

- 2 -

122-2

1 •674A

F i g . 1.

Reactions

I t has been found t h a t (SNH)^ undergoes seven types of r e a c t i o n :

(1) A d d i t i o n reactions w i t h organic substrates

(2) Adduct formation w i t h Lewis acids

(3) Hydrogen s u b s t i t u t i o n

(4) Hydrogen a b s t r a c t i o n

(5) Oxidation t o t e t r a t h i o n y l i m i d e

(6) Ring degradation

(7) A new type of r e a c t i o n , r i n g c o n t r a c t i o n e.g. i s described i n t h i s work.

to Ŝ N̂ ^ or (NSCDj,

These rea c t i o n s can also be systematised according t o the nature of

the reactants (see p. 12 ) .

- 3 -

(1) A d d i t i o n Reactions w i t h Organic Substrates

There are remarkably few reported cases of organic d e r i v a t i v e s

of (SNH)^. Two d e r i v a t i v e s (SNCONHPh)^''^ and (SNCH20H),̂ ''̂ '-'-̂ have

been made by r e a c t i o n w i t h phenylisocyanate and formaldehyde. Hydrolysis

of (SNCONHPh)^ w i t h hot hydrochloric acid y i e l d s NHPh.CO.NHPh, i n t e r -

preted as evidence t h a t the H atoms i n (SI\IH)^ are attached t o the l\l

13 atoms. The hydroxy-methylene d e r i v a t i v e (SI\ICH20H)^ has been converted to esters (SN.CH^OCOR)^ by r e a c t i n g w i t h a c y l chlorides RCOCl (R = CH^,

13

pN02CgH^) . Both are c r y s t a l l i n e s o l i d s ; the a c e t y l d e r i v a t i v e melting

a t 87.5°, and the p-nitrobenzoyl d e r i v a t i v e a t 212° with decomposition.

(2) Adduct Formation w i t h Lewis Acids

There are only two reported cases of ( S N H ) ^ adducts. Addition of

( S N H ) ^ t o an ether s o l u t i o n of TeBr^ y i e l d s an amorphous or§nge powd er

15 '

(SNH)^.TeBr^ , s t a b l e i n dry a i r , whose s t r u c t u r e has not been determined.

I t seems t o be the only reported case where a c y c l i c sulphur imide forms

a s t a b l e adduct w i t h a Lewis acid without simultaneous rearrangement or e l i m i n a t i o n . The r e a c t i o n between (SNH)^ and AgNO^ i n a c e t o n i t r i l e or

/ X 16

acetone y i e l d s (SI\IH)^.2AgN02 which may be a simple adduct, but i s

unstable, decomposing w i t h i n a few hours, immediately w i t h water (seep. 9 ) .

Two new adducts are reported i n t h i s t h e s i s . Both AlBr^ and A l C l ^

react w i t h (SNH)^ i n carbon dis u l p h i d e t o y i e l d orange (SNH)^.AlBr2 and

pale orange-yellow (SNH)^.AlCl^. These adducts are amorphous s o l i d s and

have been characterised by elemental analysis and examination of i . r .

spectra (see p. 2 7 ) . Reaction w i t h SnBr^ i n ether ( s u r p r i s i n g l y ) y i e l d s

an S^N^ adduct, 2S^N^.SnBr^. This compound was i d e n t i c a l to t h a t produced

from S^N^. '̂̂

(3) Hydrogen S u b s t i t u t i o n

There are f i v e reported cases of hydrogen s u b s t i t u t i o n i n v o l v i n g

r e t e n t i o n of the S^N^ r i n g system. An a c e t y l d e r i v a t i v e (SNCOCH^)^ 3

has been reported, by r e a c t i o n w i t h a c e t y l c h l o r i d e i n e t h y l acetate,

but we were unable to repeat t h i s preparation (seep. 31). We believe 3

t h a t t h i s r e p o r t has entered the l i t e r a t u r e through an e r r o r i n t r a n s -13

l a t i o n . Arnold described the r e a c t i o n between the hydroxy-methylene

d e r i v a t i v e (SNCH20H)^, of (SNH)^, and a c e t y l c h l o r i d e i n e t h y l acetate

s o l u t i o n containing a t r a c e of potassium carbonate y i e l d i n g the d e r i v a t i v e

(SNCH20C0CH2)^, mp 87.5°. Garcia-Fernandez however, refers"^ to the

r e a c t i o n between (SNH)^ and a c e t y l c h l o r i d e i n e t h y l acetate containing

a t r a c e of potassium carbonate to y i e l d the d e r i v a t i v e (SNCOCH^)^ mp 87.5°. 18

The reference to (SN.COCH^)^ i n a recent review i s probably also as

a r e s u l t of the same t r a n s l a t i o n e r r o r . 19

Reactions w i t h copper ( l l ) s a l t s i n non-aqueous solvents y i e l d the covalent molecules S^N^H2(CuCl)2 and S^H^H2(CuN02)2 which presumably contain metal-nitrogen bonding, while LiAlH^ i n THF gives the explosive

20 white s o l i d LiAl(S^N^) . Careful h y d r o l y s i s of the l a t t e r compound

- 5

w i t h moist acetone r e s u l t s i n formation of LiOH, Al(0H)2 and (SNH)^

i n d i c a t i n g t h a t the r i n g system i s r e t a i n e d . M. Becke-Goehring suggests

t h a t the s t r u c t u r e of t h i s compound may be ( l ) , or i t may contain the

complex anion ( l l ) . 21

I S

N .

L i

Al S

,N

A l ' S

S——^N

( I ) ( I I )

That ( S N H ) ^ can f u n c t i o n as a Br/nsted acid i s shown by the reaction 22 2— + w i t h Pĥ CIMa i n ether-dioxane. Two s a l t s ( S ^ N ^ H ^ ) "Wa ^ ( c i t r o n yellow)

and ( S ^ N ^ ) ^ ' ^ ^ ^ 4 (orange red) were i s o l a t e d and proved much more unstable

and r e a c t i v e than (SNH)^. Both formed unstable s o l u t i o n s i n polar organic

solvents and detonated or i g n i t e d w i t h water. Evidently Ph^C i s a

strong enough base to i o n i s e o f f and accept protons from the ( S N H ) ^ r i n g

which acts as a very weak Br/nsted a c i d . S ^ N H (see p. 14 ) i s a non-23 24

conductor i n p y r i d i n e , w i t h which i t hydrogen bonds , and i s vary

soluble i n t h i s s o l v e n t . I t seems l i k e l y t h a t ( S N H ) ^ , also very soluble

i n p y r i d i n e (see p. 1. ) may behave s i m i l a r l y , demonstrating t h a t p y r i d i n e

i s not a strong enough base t o remove protons from e i t h e r of these imides.

hie now re p o r t (see p. 40 ) t h a t the n-butyl carbanion i n n-butyl

l i t h i u m i s a strong enough base t o remove protons from (SNH)^. Measure-

ment of butane evolved during the r e a c t i o n suggested t h a t the yellow

s o l i d obtained was predominantly (S^N^)''^ '"•'•̂ 4*

There are no reported cases of d i r e c t a l k y l a t i o n of (SNH)^. Tetra-

a l k y l d e r i v a t i v e s have been made i n d i r e c t l y i n low y i e l d (2% or less)

by r e a c t i n g sulphur d i c h l o r i d e SCI2 with the corresponding primary amines

(see Table l ) .

R mp Reference

^ " 3 126° 25

^2^5 143° 26

^6"5^^^2 164° 27

C,H3(CH2)2 165.5° 27

(SNR)^

TABLE 1.

25 An unstable l i n e a r polymer (SNCH ) has also been reported from

the r e a c t i o n between gaseous methylamine and sulphur d i c h l o r i d e i n hexane.

There i s an apparent inconsistency i n reports of (StiC^H^)^. Lengfeld and 28

S t i e g l i t z reported t h i s compound as an o i l ( e x c e l l e n t analyses and 26

molecular weight d e t e r m i n a t i o n ) . Later workers , using i d e n t i c a l reagents

7 -

but very d i l u t e s o l u t i o n s , obtained a sharp melting s o l i d a f t e r chromato-

graphic separation. The low melting p o i n t of the Lengfeld and S t i e g l i t z

product i s probably due t o the presence of i m p u r i t i e s , possibly i n c l u d i n g

a mixture of isomers.

As i n ( N P ) ^ r i n g s ( I M P X ^ t e t r a m e r s ) , there are four r i n g conformations 29 4 5 6 (crown, saddle, tub and c h a i r ) , X-ray ' and neutron d i f f r a c t i o n

s t udies have shown t h a t (SNH)^ e x i s t s as the crown form i n the s o l i d s t a t e .

I t i s s i g n i f i c a n t t h a t the SNS bond angle (l22.2° ^) i s close t o 120°

hence there i s only one hydrogen p o s i t i o n , and no f u r t h e r isomers i n the

crown conformation. This could be as a r e s u l t of complete n i t r o g e n lone-pair

d e l o c a l i s a t i o n i . e . SN bond order 1.5 (SN bond length suggests SN bond

order of 1.3 ) , or because the lone p a i r (or at l e a s t the remaining lone

p a i r character) i s i n a p - o r b i t a l . Thus, i f the SNS angle i s nearly 120°

i n (SNC^Hg)^, there w i l l be four isomers (crown, saddle, tub and c h a i r ) ,

but i f the SNS angle i s s i g n i f i c a n t l y less than 120° then each e t h y l group

could be a x i a l or e q u a t o r i a l , ( i . e . f i v e conformational isomers i n the

crown form). Moreover, there may w e l l be i s o l a b l e conformational isomers

based on other r i n g shapes.

(4) Hydrogen Abstra c t i o n

There are two reported cases of hydrogen a b s t r a c t i o n s . Heating under

vacuum a t 110-135° produces S^N^ i n over 95^ yield'^'^ and heating w i t h

(NSC1)„ i n CCl. containing a trace of p y r i d i n e r e s u l t s i n almost q u a n t i t a t i v e v J ^

31 conversion t o S^N^ . The proposed equation i s : -

Z{sm)^ + 4(NSC1)3 — > 6S^N^ ^ 12HC1

8 -

Reaction betueen (SNH)^ and (NSCl)^ i n CCl^ wi t h p y r i d i n e absent r e s u l t s

i n formation of the red-brown adduct S^I\I^.4HC1, which reacts with a trace

of water t o giv/e S^N^CljNH^Cl and Cl^. The o v e r a l l equation i s

3(S(\1H)^ + 4(NSC1)2 > 3S^N^ + SS^N^Cl + 3NH^C1 + 301^

A f u r t h e r instance of hydrogen a b s t r a c t i o n i s reported i n t h i s t h e s i s

(see p. 3 4 ) . Reaction w i t h l\l-bromosuccinimide (1:1 molar r a t i o ) pro-

duced;- ^4'^4' "̂"̂ ^i-^^ excess l\l-bromosuccinimide ( l : 2 molar r a t i o ) S^N^Br.

(5) Oxidation t o T e t r a t h i o n y l i m i d e

The a i r o x i d a t i o n of (SNH)^ at 110-120° y i e l d i n g orange-red t e t r a -32

t h i o n y l i m i d e (SOMH)^ i s reported by Fluck and Becke-Goehring.

(6) Ring Degradation

There are several reported cases of (SNH)^ rea c t i n g with metal com-

pounds i n nonrsqueous solvents t o give metal t h i o n i t r o s y l s , 1*1 (NS) . A X y

33

green/yellow powder Hgg(NS)g r e s u l t s from r a p i d ( l 5 minutes) re a c t i o n

w i t h mercury ( l l ) acetate i n methanol (or p y r i d i n e ) a t low temperature.

This compound i s unstable forming HgS on exposure t o a i r . Slow rea c t i o n between (SNH)^ and a large excess of mercury ( l l ) acetate i n p y r i d i n e

33 forms Hg(l\IS)2. Hgg(NS)g i s considered t o be a molecular compound of

33 3Hg(l\lS)2 and Hg2(NS)2. Hgg(l\IS)g can be oxidised by t h i o n y l c h l o r i d e

33 i n s o l u t i o n t o t h i o n y l d i n i t r o s y l (NS)2S0. Reaction of Hgg(NS)g

- 9

w i t h S2CI2 giuBs t e t r a s u l p h u r d i n i t r i d e S^l\l2 (an unstable red o i l ) i n

4 2 ^ y i e l d , a r e a c t i o n uhich throws l i g h t on the s t r u c t u r e of Hq_(l\IS)_.

Hg^(NS)g + 4S2CI2 — * 4S^N2 + 3HgCl2 + Hg2Cl2

2 1 2 -This i s considered t o be euidence f o r the presence of ̂ 2^2 ligarids

i n Hgg(l\lS)g, r e a c t i n g as shown

^ 2 ^ 2 ^ " * ^2^h ~ ^

A t h i r d mercury compound (Hg(l\IS)) has been obtained as a yellow p r e c i -X

35

p i t a t e by r e a c t i o n between (SNH)^ and mercury ( l ) n i t r a t e i n DMF at

-70°. This compound i s stable a t room temperature and i s acted on slowly

by water and d i l u t e acids. I t i s q u i c k l y decomposed by strong acids and

bases. Copper (1) c h l o r i d e and s i l v e r n i t r a t e i n non-aqueous solvents y i e l d

1 9

black CuNS and red-brown AglMS re s p e c t i u e l y (see p. 3 ) . I t has been 1 9

suggested t h a t the r e a c t i n g species i n these reactions are H N S and

S ( N H ) 2 , the former y i e l d i n g the n i t r o s y l and the l a t t e r serving as an

o x i d i s i n g agent. The d e r i v a t i v e s of ( S I \ ) H ) ^ mentioned so f a r are i n s o l u b l e i n i n e r t solvents, suggesting t h a t they may be coordination polymers

W " ' ^ 2 ^ 2 c o n t a i n i n g the ligands S . N , ^ " , S n/" (see above) or S N " . Reaction 1 9

between AgNS and e t h y l i o d i d e y i e l d e d a yellow o i l , s i m i l a r to the

yellow o i l reported by Lengfeld and S t i e g l i t z as {SNC^H^)^. (see p. 6 ) .

Goehring et a l i n t e r p r e t e d t h i s as evidence t h a t the eig h t membered Sl\l

- 10

r i n g was r e t a i n e d i n the s i l v e r compound. We believe t h a t the s t r u c t u r e

of the s i l v e r compound may w e l l be (Agl\IS)^, g i v i n g on r e a c t i o n a mixture

(yellow o i l ) c o n s i s t i n g mostly of (SNC^H^)^ which would y i e l d the pure

d e r i v a t i v e ( s o l i d ) a f t e r chromatographic p u r i f i c a t i o n . 36

I t has been reported t h a t treatment of (SNH)^ i n l i q u i d ammonia wi t h lead ( l l ) acetate or i o d i d e y i e l d s the compound Pb(NS)2.NH2. Later

16 workers were unable to repeat t h i s p r e p a r a t i o n . Treatment of (SI\IH)^ i n l i q u i d ammonia w i t h potassamide KNH2 r e s u l t s i n formation of the com-

16

pound KI\1S.(\IH2K which i s immediately decomposed by moist a i r . I t i s

however f r e e l y soluble^' i n l i q u i d ammonia as long as (SNH)^ i s present.

A d d i t i o n of lead i o d i d e t o such a s o l u t i o n p r e c i p i t a t e s a mixture of

Pb(l\lS)2.NH2, PbNH and PbN.Pbl.NH^ i n d i c a t i n g the presence of various

n i t r o g e n - c o n t a i n i n g anions. Treatment of (SI\1H)^ i n p y r i d i n e w i t h h a l o - s u b s t i t u t e d benzene

37

sulphonyl c h l o r i d e s y i e l d e d a series of t h i o d i t h i a z y l compounds R2̂ 3'̂ 2 '

the s t r u c t u r e s of which are unknown (see Table 2 ) .

R Product mp

Phenyl No r e a c t i o n -3.4 dichlorobenzene Deep red s o l u t i o n no

s a t i s f a c t o r y product 2.4.5 trichlorobenzene Red (2.4.5.Cl2CgH2)2

^3^2

209°C (decomposition) Red (2.4.5.Cl2CgH2)2 ^3^2

2.5 dichlorobenzene (2.5Cl2CgH3)2S3N2 200°C (decomposition)

2.4.5 tribromobenzene Orange-red (2.4.5.Br3CgH2)2S3N2

214°C

REACTIONS BETWEEN (SNH),^ AND RSO^Cl TABLE 2

37

- 11 -

1 (SI\IH), reacts w i t h S^Cl. t o give the compound H„I\I„S„C1„. This 4 Z Z D J z o

substance i s described as a s a l t , having s i m i l a r p r o p e r t i e s t o S.N„C1

(see r e f . 8 4 ) . Reaction of (SNH ) ^ w i t h Na/EtOH gives (N H ^ ) 2 S and Na2S 3 8 3 9 and w i t h hydrogen i o d i d e gives S, I ^ and N H ^ , or (according t o Murthy )

+ 4 0 H2S, NH^I and I 2 . Hydrolysis w i t h strong acids gives NH^ , S and SO2 >

2- 4 0 and strong bases r e s u l t i n the formation also of 820^ • Oxidation of (SNH)^ w i t h chloramine -T i n a c i d i f i e d aqueous dioxane also r e s u l t s i n r i n g

4 1

degradation ( q u a n t i t a t i v e conversion of the sulphur to H2S0^) . Oxidation

without r i n g degradation i s described on p. 8,

7. Ring Contraction

Ring c o n t r a c t i o n t o Ŝ N̂ ^ and (NSCl)^ i s described i n t h i s t h e s i s .

Treatment w i t h bromine (see p. 3 3 ) or a c e t y l bromide (see p. 32 ) r e s u l t s

i n the formation of t h i o t r i t h i a z y l bromide, S^N^Br, and ammonium bromide.

S i m i l a r l y a c e t y l c h l o r i d e gives S^N^Cl and NH^Cl (see p. 3 1 ' ) . However,

r e a c t i o n w i t h c h l o r i n e (see p. 3 8 ) or su l p h u r y l c h l o r i d e (see p. 3 9 )

r e s u l t s i n the formation of t r i t h i a z y l t r i c h l o r i d e (NSCl)^.

- 12 -

AIR OXIDWION 110-120*

S N , S , N H ^ U h C E R ^ ^ 110-135°

HCHO — . (SNCH^H)^-•(SNCHgOOORJi

PhNCO — . (SNCONHPh)^

N H ^ . S , S 0 2 — / G D

N H ; . S . S 0 2 , ^ c f ^ B A S E \ ^

STRONG AC1D

STRONG SASE

Na/EtOH REDUCTION 6 (SNH)

ORGANIC ADDITION HEATING

ADDUCTS

HYDROGEN

SUBSTITUTION

— Bir

METALS r-

S N B r 4 3

(NsaL CL

Tea; — » (SNHhTiaa: 4 4 4

-(SN^^^2AgN02

* ( S f * 4 j ^ O - • 4 3

4 3

Sr f i r — ( S N j ^ : S n B r ^ -

H E ^ ^ 2 ^ ( H r f N S ) ^

CuQ 0 / 6

At fCi j — A ^

(srFtfQKd,

ACYL

HALIDES

N-HAL

N-BrCTTOsuccinirride

SN_a OHoramina-T

* P b ( N S ^

> K N S J * y (

Q i N O j , - ^ S N H ^ Q i « 3 ) 2

UAIH — . LIAXSN) 4 4 4

^ S N H ^ f ^ . | N N a ,

4̂̂ 4»

.(Nsa)^ • S N / S ^ N ^ ^ N . ^ )

R&aCTIONS O F T E T R A T H O T E T R A I M I D E ( *TH1S WORK)

Flo. 2.

13

2. Other Sulphur Imides Derived from Octasulphur. 42 Imides derived from octasulphur are discussed i n a recent review ,

a b r i e f summary of which i s given here.

Imides contain the b i v a l e n t N̂H group which can take the place of a

d i v a l e n t sulphur atom i n the Ŝ r i n g . Imide hydrogens are somewhat a c i d i c , b

and are also l a b i l e towards sulphonation, a c y l a t i o n etc.

Up t o 4 sulphur atoms i n the Sg r i n g have been replaced by ^NH groups

and a l l possible imide d e r i v a t i v e s up t o (SNH)^ are known. Replacement of

more than f o u r sulphur atoms r e s u l t s i n adjacent NH groups, and, although

there i s no reason wĥ :.;. such compounds should not be preparable (e.g. from

N2H^ and sulphur h a l i d e s ) , none i s known. However, i t seems l i k e l y t h a t i f

they could be made they would e a s i l y e l i m i n a t e molecular n i t r o g e n .

There are two general methods of making these imides. F i r s t , reduction

of sulphur n i t r i d e s . The reduction of Ŝ N̂ w i t h stannous c h l o r i d e to give 2 43

(SNH)^ has already been described i n t h i s t h e s i s and Garcia-Fernandez *

has reduced t e t r a s u l p h u r t e t r a n i t r i d e and t h i o t r i t h i a z y l c h l o r i d e w i t h

hydrazine on s i l i c a g e l t o obtain heptasulphur imide S,̂NH i n good y i e l d ,

w i t h smaller amounts'of the d i - , t r i - , and t e t r a i m i d e s . The second general

method i s t o react ammonia wi t h a sulphur c h l o r i d e i n a polar solvent,

generally D|vip^4,45,46,47,48,4g,50,51^ ^^^^ produced i n good y i e l d s by t h i s method, along w i t h the d i - and t r i i m i d e s i n much smaller q u a n t i t i e s ,

52

separation being e f f e c t e d by chromatography on s i l i c a gel . S i m i l a r y i e l d s

of Ŝ NH and of the diimides are obtained by adding a CCl^ or CS2 s o l u t i o n

14

of S2CI2 t o aqueous a m m o n i a ' ^ ^ ' T h e r e a c t i o n of azides w i t h chloro-

sulphanes i n polar solvents t o give these imides has also been reported.

( i ) Heptasulphur Imide Ŝ NH

Ŝ NH i s a s t a b l e , almost c o l o u r l e s s c r y s t a l l i n e s o l i d m.p. 113.5°

i n s o l u b l e i n , and not a f f e c t e d by, water. I t i s r e a d i l y soluble i n most 47

organic solvents and i s very soluble i n p y r i d i n e to which, as the i . r .

spectrum shows, i t hydrogen b o n d s . T h e S-N bond lengths correspond t o

a bond order of 1.3, suggesting some d e l o c a l i s a t i o n of the nitrogen lone-

p a i r .

( i i ) The Hexasulphur Diimides, S^(NH)2.

A l l t h r e e isomers 1,3-, 1,4- and 1,5- hexasulphur diimide have been

isolated^"^' ^ Their s t r u c t u r e s were deduced from X-ray d i f f r a c t i o n

s t u d i e s ^ ' ' ' e x a m i n a t i o n of i . r . spectra (showing s p l i t t i n g of the SN

s t r e t c h i n g frequency due t o i n t e r a c t i o n between NH groups as they become

closer)^''', and measurement of di p o l e moments which agreed with calculated 48

values based on vector a d d i t i o n of c o n t r i b u t i o n s from the imide groups.

The hexasulphurdiimides are c o l o u r l e s s , c r y s t a l l i n e compounds, 'almost i n -

d e f i n i t e l y s t a b l e ' when pure, though the 1,4- isomer darkens s u p e r f i c i a l l y 59

on exposure t o d a y l i g h t . (i±L) The Pentasulphur T r i i m i d e s S ^ ( N H ) ^

These imides are present i n very small q u a n t i t i e s i n the r e a c t i o n product 48

from S2CI2 and ammonia i n DMF, and can be i s o l a t e d by chromatography.

There are two reported isomers; the 1,3,5- and 1,3,6- t r i i m i d e s , both

- I t ) -

S'1078

1.68J1 .S./ H .109.0'

(B)

S

S

(C)

118' 110°

^ 2.04 X\s^^,

D)

A73A

(R

FiQ> 3.

Plolecular structured of octaaulphur and the imides derived from i t , shouing dimensions uhere knoun.

(A) Sg, rhombic, ;

(0) l,4TS6(NH)2r (G) 1,3,6-S5(NH)3,

(B) Ŝ NH, (E) l,5-Sg(NH)2, (H) S^CNH)^,

(C) l,3-Sg(NH)2, (F) It3,5-S5(NH)3,

- 16 -

being c r y s t a l l i n e s o l i d s . The former can also be prepared by hydrazine 2

reduction of Ŝ N̂ , and i t seems l i k e l y t h a t the 1,3,6- isomer could also 2

be made i n t h i s way. The s t r u c t u r e of the 1,3,5- isomer has been determined

by X-ray d i f f r a c t i o n studies.^'^

Reactions

The r e a c t i o n s o f the imide.s S^NH, Sg(NH)2 and Sg(NH)3 w i l l be divided

i n t o r e a c t i o n types so t l i a U ^ ' c j i m i l a r i t i e s and dif f e r e n c e s i n behaviour can

be compared w i t h these of (SNH)^.

(1) A d d i t i o n Compounds wi t h Organic Substrates

Like (SNH)^ (p. 3. ) , Ŝ NH forms a c r y s t a l l i n e d e r i v a t i v e S^NCH20H

wi t h formaldehyde.^''' There are no reported cases of t h i s type of re a c t i o n

f o r the other imides.

(2) Adduct Formation w i t h Lewis Acids

( S N H ) ^ forms simple adducts w i t h Lewis acids (see p. 3. ) No

r e a c t i o n i s known i n which the other imides add on to a Lewis acid without

simultaneous rearrangement or e l i m i n a t i o n . Ŝ NH reacts with boron t r i h a l i d e s

i n CS2 a t low temperatures (below -40°) t o give the compounds S^NBCl2 and 62

S^MBBr2. Sulphur t r i o x i d e gives a carmine red 1:1 compound wi t h S.̂ NH,

which by analogy w i t h other reactions of SO3 i s probably a sulphonic acid

S,NS03H.^^'^^ (3) Hydrogen S u b s t i t u t i o n

Unlike (SNH)^, which has not been acylated (see p. 4. ) , Ŝ NH and the

hexasulphur diimides can be acylated by standard methods g i v i n g c r y s t a l l i n e

organic d e r i v a t i v e s , those of Ŝ NH being prepared i n high y i e l d s . ( S e e

Table 3 ) .

17

ACYL DERIUATIWES OF SULPHUR INIDES

R o„ mp C Ref.

Ŝ NCOR 104 65,66,67

CH2CI 110 65

^6^5 138 65

^^^2^6^5 110 65

(CH2)^CH3 Liq u i d 65

(CH2),6CH3 58 65

CH = CHCgHg 146 65

o-ClC^H. D 4

92 65

p-N02CgH^ 136 65

S^NC0(CH2)2C0NS^ 195 68

l,3-SgN2(C0R)2 ^^3 130 68

^6^5 unstable 68

l,4-SgN2(C0R)2 ^"3 77 68

^6^5 156 68

l,5-SgN2(C0R)2 158 68

6̂̂ 5̂ 183 68

TABLE 3

- 18

69 A t r i m e t h y l s i l y l d e r i v a t i v e S^N.Si(CH3)3 has also been reported, and

Ŝ NH forms methylene diamine d e r i v a t i v e s of the type Ŝ NCH2NR2 (R = CH3,

C^H^, C^Hg) w i t h N-hydroxymethyl dialkylamines R2NCH20H.'̂ ^ Ŝ NH and (SNH)^ 76

give s i m i l a r d e r i v a t i v e s w i t h N-hydroxymethylpiperidine.

Mercury d e r i v a t i v e s of Ŝ NH have been prepared; Hg(NS^)2, nearly

white, and Hg2(NS^)2, yellow, by r e a c t i o n with mercury ( l l ) acetate i n

methanol and mercury ( l ) n i t r a t e i n DMF r e s p e c t i v e l y ( c f . p. 8. ) .

The s t r u c t u r e s of these compounds are unknown, but i t i s suggested t h a t

Hg(NS^)2, somewhat soluble i n carbon d i s u l p h i d e , i s covalent with the simple 21

monomeric formula shown.

The imides f u n c t i o n as weak Br/nsted acids i f a strong enough base i s

a v a i l a b l e . The t r i p h e n y l m e t h y l carbanion i n Ph3CNa removes protons from 22

both Ŝ NH and (SNH)^ , the methyl carbanion i n methyl magnesium iodide does the same w i t h Ŝ NH and l,5-Sg(NH)2,^''"''''^ and Olsen e t . a l . r e p o r t t h a t

71 Na, NaNH2, NaH, LiOH and e t h y l l i t h i u m a l l deprotbnate Ŝ NH. The isomeric

71

forms of Sg(NH)2 behave s i m i l a r l y w i t h e t h y l l i t h i u m , and the removal of

protons from (SNH)^ by n- b u t y l l i t h i u m i s described i n t h i s t h e s i s (p. 40 ) .

There are no r e p o r t s of " d i r e c t " i . e . s i n g l e stage a l k y l a t i o n of these

sulphur imides. A l k y l d e r i v a t i v e s have been produced i n two ways; f i r s t l y by r e a c t i n g an a l k y l h a l i d a w i t h the l i t h i u m s u b s t i t u t e d imide ( i . e . the

71 imido a n i o n ) , and secondly by r e a c t i n g primary amines with sulphur chlorides . . ^ , ^ 25,26,27,72. m i n e r t s o l v ents.

19

ALKYL DERIUATIUES OF SULPHUR i n i D E S

R 0̂ mp C Ref.

Ŝ IMR ^^3 Yellow o i l 71

CH2=CHCH2 Yellow o i l 71

CgH5CH2 Yellow o i l 71

2̂̂ 5̂ Yellow o i l 71

(CH3)2CH Yellow o i l 71

l,5-Sg(NR)2 ^^3 77 72 81.5-82 71

1,5S^.NH.I\IR •

100.5-102 71

l,4Sg(WR)2 ^^3 24.5-25.5 71

l,4Sgl\IH.I\IR 51.5-53 71

l,3,5S5(l\IR)3 45 25

l,3,6Sg(NR)3 55 25

^6^5^^^2 150 26

CgH5(CH2)2 89 26

(SNR)^ 126 25

^2^5 143 26

^6"5^^2 164 27

^6^5(^^2)2 . 165.5 27

TABLE 4

20 -

Heal e t . a l . mention p r e l i m i n a r y work on the r e a c t i o n between S2CI2

and aqueous methylamine y i e l d i n g the methyl d e r i v a t i v e s of Ŝ NH, a l l three 73

hexasulphur diimides and at l e a s t one of the psntasulphur t r i i m i d e s . 25

( c f . r e a c t i o n i n hexane between gaseous methylamine and SCI2 ) .

An i n t e r e s t i n g d i f f e r e n c e i n behaviour i s observed i n the r e a c t i o n of

these imides w i t h disulphur d i c h l o r i d e . Arnold reported t h a t (SNH)^ gave a white s a l t HgN3S2Cl3 w i t h p r o p e r t i e s s i m i l a r t o S^N3C1 on reac t i o n with

13 S2CI2. The other imides, however, give a condensation r e a c t i o n of form

CS2 ^NH + C1-S-5-C1 + HN< > )N-S-S-N

- 21 -

(6) Ring Degradation 38 Heptasulphur imide reacts r e a d i l y w i t h HI according to the equation

Ŝ NH + 2HI > 7S + I2 + NH3

T e t r a t h i o t e t r a i m i d e reacts s i m i l a r l y (see p. 11 ) . On rea c t i o n with

(NSCl)^* the Ŝ I\IH r i n g i s destroyed, sulphur being formed according to the 31

equation 4(l\ISCl)2 + 12Ŝ I\1H > 6S^I\I^ + 12HC1 + 725

This r e a c t i o n may be compared w i t h t h a t of (SI\IH)^ i n s i m i l a r conditions 31

where hydrogen a b s t r a c t i o n occurs and the Ŝ N̂ r i n g i s r e t a i n e d . (see p. 7 ) Oxidation of heptasulphur imide, w i t h chloramine-T i n a c i d i f i e d aqueous

dioxane also r e s u l t s i n r i n g degradation ( q u a n t i t a t i v e conversion of sulphur 41

t o H2S0^) . T e t r a t h i o t e t r a i m i d e behaves s i m i l a r l y (see p. 11 )

(7) Ring Contraction

The re a c t i o n s of (SI\)H)^ w i t h c h l o r i n e , s u l p h u r y l c h l o r i d e , bromine, and

a c e t y l bromide reported i n t h i s t h e s i s are the only known examples of t h i s

r e a c t i o n type.

- 22 -

EXPERIMENTAL

Handling Techniques

As many of the compounds dea l t w i t h were s e n s i t i v e to moisture,

operations were c a r r i e d out i n an atmosphere of dry ni t r o g e n . Traces of

water were removed from the nitr o g e n by passing through two traps cooled

i n l i q u i d n i t r o g e n . Operations which were i m p r a c t i c a l or inconvenient

under counter-current n i t r o g e n were c a r r i e d out i n a glove box.

I n f r a r e d Spectra

I n f r a r e d spectra wer? recorded on Grubb-Parsons prism g r a t i n g spectro-

meters; the 5pectromaste.r and GS2A were used f o r the range 4000 - 400 cm ̂ .

Samples of solidswere prepared as n u j o l mulls, l i q u i d s were examined as

contact f i l m s , and gases were i n v e s t i g a t e d i n gas c e l l s . The mull or l i q u i d

was supported between sodium c h l o r i d e or potassium bromide plates as was

ap p r o p r i a t e . The f o l l o w i n g symbols are used t o denote the r e l a t i v e

i n t e n s i t i e s of i . r . absorptions: vs - very strong; s - strong; m - medium;

w - weak; vw - very weak; sh - shoulder; and b - broad.

P u r i f i c a t i o n of Solvents

Hydrocarbons and D i e t h y l Ether were d r i e d over excess sodium wire f o r

at l e a s t 48 hours before use.

Tetrahydrofuran was stored over LiAlH^ and d i s t i l l e d as required.

Carbon T e t r a c h l o r i d e was d r i e d over P2'^5 l e a s t 48 hours before

use.

Chloroform was stored over molecular sieve 4A.

23 -

Pyr i d i n e was stored over NaOH and d i s t i l l e d on to fresh NaOH f o r

use as re q u i r e d .

Carbon dis u l p h i d e was s t i r r e d w i t h mercury f o r 12 hours, d i s t i l l e d

on t o P2'̂ 5 3nd then d i s t i l l e d as required f o r use.

E t h y l Acetate t e c h n i c a l grade was d i s t i l l e d before use.

Preparation of S t a r t i n g M a t e r i a l s

T e t r a t h i o t e t r a i m i d e 12

The method used a t f i r s t was t h a t described by Brauer. 20g. Ŝ N̂

dissolved i n 600 ml. dry benzene were heated t o 80° i n a 2 l i t r e f l a s k on

an o i l bath. A s o l u t i o n of 70g. SnCl2.2H20 i n 160 ml. methanol containing

about S% water was added a l l a t once. The s o l u t i o n began t o b o i l and did

so v i g o r o u s l y f o r nearly an hour u n t i l i t was col o u r l e s s . The p r e c i p i t a t e

was s u c t i o n f i l t e r e d and washed w i t h 2ri HCl u n t i l no t i n remained. Washing

w i t h a l c o h o l removed l a s t traces of colour and f i n a l l y washing with ether

gave shiny c o l o u r l e s s c r y s t a l s . Y i e l d 12g. R e c r y s t a l l i s a t i o n i f required,

i s from methanol. This preparation was less than s a t i s f a c t o r y i n four ways!

( i ) a d d i t i o n of methanolic stannous c h l o r i d e produced very vigorous

b o i l i n g r e s u l t i n g i n the reactants b o i l i n g out of a 2 l i t r e f l a s k ,

( i i ) i t was not u s u a l l y possible t o add the stannous c h l o r i d e s o l u t i o n

" a l l a t once" because of the vigorous r e a c t i o n ,

( i i i ) the s o l u t i o n d i d not go colourless as described but often retained

an orange colour i n d i c a t i n g unreacted Ŝ N̂ , ( i v ) r e c r y s t a l l i s a t i o n from methanol r e s u l t e d i n the loss of most of

the m a t e r i a l and the product was oft e n l i t t l e b e t t e r . A repeat preparation

- 24

i s preferable i f poor analyses are obtained.

Accordingly a modified procedure, described here, was worked out,

lOg. Ŝ N̂ i n 300 ml. dry benzene was heated to 80° i n a 5 l i t r e flange

top flask f i t t e d with a wide neck condenser and s t i r r e r . A solution of

35g. SnCl2.2H20 i n 80 ml. methanol containing 5^ water was added a l l at

once to the solution when reflux had Just stopped and a further long

necked condenser had been f i t t e d to the flange top. Care should be exercised

at t h i s point for i f the solution i s refluxing uigorously bumping w i l l

occur, pushing the reactants out of the flask. When the exothermic reaction

was completed, the solution was again heated to ref l u x , and, using the same

procedure as before, a further 35g. SnCl2.2H20 i n 80 ml. methanol was added.

The solution turned from yellow to almost white. The products were allowed

to cool and then f i l t e r e d through a sinter, washed with IDD ml. 2M HCl, then

with 100 ml. ethanol and f i n a l l y with 100 ml. ether to leav/e pale buff

crystals. Melting point 156°. Yield 5g.

Planqanese ( l l ) and Iron ( l l ) chlorides were refluxed with SOCI2 for 24

hours and 2 hours respectively, and then dried i n vacuo.

Aluminium bromide was p u r i f i e d by sublimation on to a water cooled cold-

finger. The containing vessel was evacuated, then sealed and maintained

at 80° f o r the sublimation. 17a

Aluminium chloride was supplied by G. G. Alange.

Tin tetrabromide was d i s t i l l e d under vacuum.

Trimethylchlorosilane, Acetyl chloride and Acetyl bromide were d i s t i l l e d

before use.

- 1^ -

N-BromodiphenylkBtimins uas supplied by K. Farmery.^'''^

Hydrogen chloride prepared from NH^Cl (Uoltoids) and concentrated sulphuric

acid was dried by passage through a long (50 cm.) ^r^c^ tube.

Benzoyl and Sulphuryl chlorides were d i s t i l l e d before use.

Tetrachloroethylene was dried ouer CaH2 and d i s t i l l e d before use.

I^ethyl Iodide, lodobenzene and Acetic anhydride were d i s t i l l e d before use.

Ethylene oxide and Epichlorohydrin were supplied by G. G. Alange. 94

n-Butyl Lithium was standardised by the method of Watson and Eastham.

1 mg. phenanthroline was added to 5 ml. of the Bu'^Li solution i n 20 ml.

benzene, gluing a rust red complex. The solution was t i t r a t e d using M

sec-butanol i n xylene, a sharp disappearance of the colour taking place

aft e r addition of 1 mole equivalent of the t i t r a n t .

27

SECTION I

METAL HALIDES

Tetrathiotetraimide and nanganese Chloride 19

Precedure according to Goehring, Weiss and Zirker. Tetrathio-

tetraimide (0.9 g., 4.8 m.mole) i n pyridine (ID ml.) was added to anhydrous

manganese chloride (4.2 g., 33 m.mole)'suspended i n pyridine (lOO ml.) at

20°. The mixture was refluxed for 48 hours, the pyridine turning dark

brown. The pyridine was euaporated under reduced pressure and the residual

brown s o l i d washed with water, ammonium hydroxide solution, acetone u n t i l

washings colourless, and ether. The pale brown sol i d gaue a weak i . r .

spectrum showing no trace of Sl\l absorption and was not inuestigated further.

Tetrathiotetraimide and Iron ( l l ) Chloride

Tetrathiotetraimide (0.15 g,, 0.8 m.mole) i n pyridine (5 ml.) was

added to anhydrous iron ( l l ) chloride (0.6 g., 4.7 m.mole) i n pyridine

(40 ml.) at 65°. The orange solution showed no change after 7 hours and

was then heated under reflux for 48 hours, during which time the colour

darkened. The pyridine was ev/aporated under reduced pressure and the res-

idual black s o l i d washed with water, ammonium hydroxide solution, acetone

u n t i l washings colourless, and ether. The golden brown solid obtained was

found, on analysis, to contain no sulphur and was not inuestigated further.

Tetrathiotetraimide and Aluminium Bromide

Aluminium bromide (l.B^i^ g., 6.9 m.mole) i n carbon disulphide (20 ml.)

was added to a s t i r r e d mixture of tetrathiotetraimide (l.30 g., 6.9 m.mole)

and carbon disulphide (lO ml.) at -196° and the reaction mixture was

- 28 -

allowed to warm to 20°. An orange flocculent s o l i d precipitated from the

orange solution, darkened and f i n a l l y lightened to pale orange. After no

further colour change.was v i s i b l e (4-^ hours) the orange product was f i l t e r e d ,

washed with carbon disulphide and dried i n vacuo (2.46 g., 78^). (Found:

Br,53.7; S,27.6j (SI\IH)^.AlBr2 requires: Br,52.7; 5,28.2). I . r . absorptions

(cm'"̂ ) a t : 3174m, 1511w, 1404s, 1294w, 1126m, 852m, 824s, 539w, 459w.

Tetrathiotetraimide and Aluminium Chloride

Tetrathiotetraimide (0.76 g., 4.0 m.mole) was added to aluminium

chloride (0.53 g., 4.0 m.mole) under carbon disulphide (30 ml.) at -196°.

The s t i r r e d mixture was allowed to warm to room temperature (20°) the solid

quickly turned brown (solvent yellow) then slowly turned red and f i n a l l y

pale orange-yellow.

After further s t i r r i n g ( t o t a l 24 hours at 20°), the mixture was f i l t e r e d ,

washed with carbon disulphide and dried i n vacuo. (0.8 g., 62^) (Found:

Al,8.7; (\),16.9. (SI\)H)^.AlCl^ requires: Al,8.4; l\l,17.4). I . r . absorptions

(cm"-"-) at : 3247m, 3252m, 3200m, 1412s, 1295w, 1261w, 1143w, 975w, 935y/,

823s, 741w.

Tetrathiotetraimide and Tin Tetrabromide

Tin tetrabromide (3.3 ml., 10.9 g., 2.5 m.mole) was added to t e t r a -

thiotetraimide (0.47 g., 2.5 m.mole) under diethyl ether (30 ml.) at -196°

and the s t i r r e d mixture was allowed to reach 20°. The solution and suspension

slowly turned dark red. After 60 hours, the suspension was f i l t e r e d , washed

with diethyl ether and dfied i n vacuo. The dark red product turned yellow

a t 184° but did not melt below 300 . (Found: Br,59.7; 3,50.86, 12.4, 11.76;

29

N,6.13, 17.69, 7.]). No serious attempt was made to solue the analytical

problem posed by these e r r a t i c analyses since the i . r . spectrum corres-17

ponded exactly to that of 2S^N^.SnBr^ (prepared from Ŝ N̂ and SnBr^ )

with extra peaks corresponding to NH^Br. There were no signs of absorptions

due to Ŝ N̂ or (SI\1H)̂ i n the i . r . spectrum of the dark red so l i d .

Dark Red Solid 2S^N^.SnBr^ NĤ Br

3175 m 3175 s 1724 uw 1700 m 1403 s 1403 s 1156 w 1156 uw 1156 w 1041 us 1041 us 961 us 961 us 926 wsh 926 uw 794 us 794 us 725 w 725 uw 725 m 671 m 671 m 621 mb 621 mb 563 w 563 w 513 m 513 m

Absorptions (cm )

30

SECTION I I

OTHER HALIDES

Tetrathiotetraimide and Trimethylchlorosilane

Trimethylchlorosilane (4 ml., 29 m.mole) was added to t e t r a t h i o -

tetraimide (0.4 g., 2.1 m.mole) and refluxed for 9 hours. Excess t r i -

methylchlorosilane was removed by evaporation under reduced pressure. The

i . r . spectrum of the off-white s o l i d obtained was identical to that of

tetrathiotetraimide.

The reaction was repeated i n pyridine. Tetrathiotetraimide (0.19 g.,

1 m.mole) i n pyridine (5 ml.) was added to trimethylchlorosilane (4 ml.,

29 m.mole) i n pyridine (10 ml.) and heated to refl u x . After one hour the

suspension was f i l t e r e d to give a white so l i d and red solution which, on

evaporation under reduced pressure, yielded a red-brown s o l i d . The i . r .

spectrum of the red sol i d showed traces of tetrasulphur t e t r a n i t r i d e but 77

no trace of t r i m e t h y l s i l y l peaks.

I . r . absorptions shown by red s o l i d (cm '''): 1266w, 1163w, 1053w, 1005w,

926s, 800w, 752s, 728m, 699s, 685s, 610m, 551sh, 546s.

I . r . absorptions shown by trimethylchlorosilane (cm '''): 2977s, 2912m,

1454w, 1415w, 1260s, 857s, 767m, 700w, 640m, 487m.

The i . r . spectrum of the white so l i d was id e n t i c a l to that of pyridine 78

hydrochloride ; again there were no signs of t r i m e t h y l s i l y l absorptions.

This reaction was not studied further.

- 31

Tetrathiotetraimide and Acetyl Chloride

(1) Procedure according to Garcia-Fernandez.

Acetyl chloride (1.5 ml., 21 m.mole) was added to tetrathiotetraimide

(0.76 g., 4 m.mole) and potassium carbonate (1.25 g., 9 m.mole) under

ethyl acetate (30 ml.). At 20° the mixture was s t i r r e d for 16 hours,

during which time the ethyl acetate turned orange, and was then f i l t e r e d .

A white s o l i d (A) remained on the sinter and euaporation of the f i l t r a t e

under reduced pressure gaue a red-brown solid (B). The i . r . spectra of

the white and red-brown solids indicated (A) unreacted tetrathiotetraimide

and (B) a mixture of tetrathiotetraimide and tetrasulphur t e t r a n i t r i d e

respectiuely.

The reaction was repeated i n absence of potassium carbonate (2) i n

ether, and (3) using excess acetyl chloride and no other soluent.

( 2 ) Acetyl chloride (2.0 ml., 28 m.mole) was added to a s t i r r e d mixture

of tetrathiotetraimide (0.38 g., 2 mvmole) and diethyl ether (30 ml.) at

20°. The ether turned pale yellow within 3 hours and orange within 24

hours. After 120 hours, the sol i d had turned yellow and as no further

change occurred, the mixture was f i l t e r e d after 150 hours. Euaporation

of the f i l t r a t e under reduced pressure gaue a dark o i l which was not

inuestigated further. The i . r . spectrum of the yellow solid indicated

32

the presence of both unreacted tetrathiotetraimide and t h i o t r i t h i a z y l

chloride.

( 3 ) Acetyl chloride (20 ml., 280 m.mole) was added to tetrathiotetraimide

(0.5 g., 2.65 m.mole) and the s t i r r e d suspension heated under reflux. The

acetyl chloride quickly turned yellow, orange and f i n a l l y yellow. After

24 hours the yellow suspension was f i l t e r e d . A pale yellow solid remained

on the si n t e r . The f i l t r a t e was evaporated under reduced pressure to

give a small quantity of yellow-brown solid which was not investigated

further. Analysis and the i . r . spectrum of the insoluble yellow s o l i d ,

by far the major product, indicated a 1:1 mixture of t h i o t r i t h i a z y l and

ammonium chlorides. (Found: N,21.1; CI,25.9. 1:1 mixture of S^N^Cl and

NH^Cl requires N,21.6; CI,27.4). . - 1 .

I . r . absorptions (cm ) occurred at:Al754w, 1403s, 1299w, 1166m, 1129vw,

1005s, 787w, 775w, 725w, 683s, 645vw, 610vw, 565s, 474sh, 467vs, 453s.

Tetrathiotetraimide and Acetyl Bromide

Acetyl bromide (3.0 ml., 5.0 g., 40 m.mole) was added to t e t r a t h i o -

tetraimide (0.94 g., 5 m.mole) under diethyl ether (30 ml.) at -196°.

The s t i r r e d mixture rapidly turned brown as i t warmed to room temperature

( 2 0 ° ) and gradually changed to give an orange-red solution and yellow

prec i p i t a t e . The mixture was s t i r r e d (12 hours, 20°) and f i l t e r e d . The

yellow s o l i d was washed with ether u n t i l washings were colourless, and

dried i n vacuo. Analyses and the i . r . spectrum indicated a 1:1 mixture

of t h i o t r i t h i a z y l bromide and ammonium bromide; the l a t t e r was removed

by washing with 98^ formic acid. Water was found to be much less e f f i c i e n t

for leaching out the ammonium s a l t . (Found: l\l,16.85; S,52.7. Ŝ |\)̂ Br

- 33

requires N,16.8; S,51.3).

- The f i l t r a t e was examined using uapour pressure chromatography,

(retention times being expressed as distances (cm.) on chart paper from

i n j e c t i o n of sample) comparing obserued retention times with retention

times giuen by pure l i q u i d s .

Pure Liquid Retention time Pure Liquid (cm.)

Ether 4.05 Acetyl bromide 6.4 Acetic acid 8.7 Diacetyl 6.05

Sample

Retention time Source (cm.)

4.05 Ether 6.4 Acetyl bromide 7.6 Unknown

Instrument: Pye 104 Chromatograph

Column length: 10 f t . 0

Column temperature: 90

Static phase: 10% Apiezon L on c e l i t e

Volume of sample: 1 ^ l i t r e

Further work to i d e n t i f y the substance responsible for the peak at

7.6 cm. was not carried out.

Tetrathiotetraimide and Bromine

Bromine (2.0 ml., 5.9 g., 36 m.mole) i n chloroform (20 ml.) was added

to tetrathiotetraimide (0.94 g., 5 m.mole) under chloroform (40 ml.)

at -196°. The reactants were allowed to warm to 20° and s t i r r e d for 24

hours. The deep yellow so l i d (dark red solution) was f i l t e r e d and pumped

dry. Analyses and the i . r . spectrum corresponded to a 1:1 mixture of

Ŝ Ŵ Br and NH^Br. The l a t t e r could be remoued by repeated washing with

34 -

formic acid. I . r . absorptions (cm"''') at: 1156s, 995s, 719w, 676w,

559w.

Tetrathiotetraimide and N-Bromosuccinimide

(a) Stoichiometry 1:1

Tetrathiotetraimide (0.94 g., 5 m.mole) dissolued i n tetrahydrofuran

(20 ml.) was added to N-bromosuccinimide (0.89 g., 5 m.mole) i n te t r a -

hydrofuran (20 ml.) at -196°. A red suspension, quickly turning yellow,

was obtained as the s t i r r e d mixture warmed to room temperature (20°).

After 20 minutes at 20° the mixture was f i l t e r e d and the f i l t r a t e euaporated

under reduced pressure. The dark brown residue was extracted with ether

and the extract on r e c r y s t a l l i s a t i o n from hexane yielded succinimide ( i n -

soluble) and tetrasulphur t e t r a n i t r i d e . Both products were i d e n t i f i e d

from t h e i r i . r . spectra.

(b) Stoichiometry 1:2

N-Bromosuccinimide (4.27 g., 24 m.mole) i n tetrahydrofuran (50 ml.)

was added to tetrathiotetraimide (2.2 g., 12 m.^TJole) i n tetrahydrofuran

(40 ml.) at -196°. A red suspension, quickly turning yellow, was obtained

as the s t i r r e d mixture warmed to room temperature (20°). After 20 minutes

at 20° the mixture was f i l t e r e d . Euaporation of the f i l t r a t e under re-

duced pressure yielded a small quantity of dark brown residue, which on

extraction witin ether and r e c r y s t a l l i s a t i o n from hexane, gaue tetrasulphur

t e t r a n i t r i d e , i d e n t i f i e d by i t s i . r . spectrum. The i . r . spectrum of the

insoluble yellow s o l i d , the major product, indicated a mixture of t h i o t r i -

t h i a z y l and ammonium bromides.

35

Tetrathiotetraimide and N-Bromodiphenylketimine

N-Bromodiphenylketimine (0.78 g., 3 m.mole) i n tetrahydrofuran (8.5 ml.)

was added to tetrathiotetraimide (0.57 g., 3 m.mole) i n tetrahydrofuran

(15 ml.) at -196°. The mixture was allowed to warm up becoming a bright

yellow suspension while s t i l l well below 0°. No further change was observed

on warming to room temperature (20°) and the suspension was f i l t e r e d (20

minutes reaction time at 20°) to give a white so l i d on the sinter and a

red/green f i l t r a t e . Evaporation of the f i l t r a t e under reduced pressure

yielded a red sol i d which would not mull and was not investigated further.

The i . r . spectrum of the white solid contained absorptions due to

tetrathiotetraimide and also absorptions very closely resembling those of

diphenylketimine hydrobromide, Absorptions (cm )

White Solid Ph2CNH 2^^ (SNH)^ 3306 (sh) 3306 (sh) 3289 (m) 3289 (s) 3226 (m) 3226 (s) 3125 (s) 3125 (s) 2920 (s) 2900 (s) 2857 (s) 2778 (m) 2778 (m) 2667 (Ui) 2667 (ui) 2516 (vw) 2516 (vw) 1923 (vw) 1923 (vw) 1842 (vw) 1842 (vw) 1736 (ui) 1736 (u.) 1653 (vs) 1653 (vs) 1600 (s) 1600 (s) 1458 (vs) 1460 (s) 1380 (vs) 1380 (s) 1328 (vw) 1325

36 -

1299 (m) 1300 (m) 1299 (m) 1190 (Ui) 1193 M 1163 (s) 1167 is) 1139 (s) 1139 (s) 1075 (uw) 1075 (uw) 1031 (UJ) 1031 (u.) 1010 (uw) 1010 (uw) 1000 (m) 1000 (m) 982 (uw) 982 (uw) 943 (^) 943 M 910 (us) 910 (us) 870 (m) 870 (m) 851 (msh) 851 (w) 851 (sh)

830 (u) 826 (us) 811 (uw) 826 (us) 797 (us) 797 (us) 758 (m) 758 (m) 726 (s) 726 (s) 703 (us) 703 (us) 696 (sh) 696 (sh) 699 (uw) 639 M 639 (s) 614 (s) 614 (s) 565 (s) 565 (s) 540 (b) 540 (b) 459 (ui) 459 (s) 446 M 446 (u)

The reaction was repeated i n toluene. N-Bromodiphenylketimine (1.04 g.,

4 m.mole) i n toluene (10 ml.) was added to tetrathiotetraimide (0.75 g.,

4 m.mole) under toluene (15 ml.) at -196° and the s t i r r e d mixture allowed

to warm to room temperature (20°). The toluene turned brown within 20

37

minutes and red within 1 hour, much creamy solid being present. After

one further hour, the suspension was f i l t e r e d leaving a white solid on

the s i n t e r . On evaporation of the f i l t r a t e under reduced pressure yellow

crystals formed, which, af t e r drying i n vacuo, were i d e n t i f i e d by the

i . r . spectrum as tetrasulphur t e t r a n i t r i d e . The i . r . spectrum of the

white s o l i d was i d e n t i c a l to that of the white solid obtained i n the

f i r s t reaction, save that those peaks corresponding to tetrathiotetraimide

were much stronger. The white so l i d was washed three times with t e t r a -

hydrofuran (10 ml.), to remove tetrathiotetraimide. The i . r . spectrum

of the so l i d washed out of the white solid indicated a mixture of t e t r a -

sulphur t e t r a n i t r i d e and tetrathiotetraimide. The i . r . spectrum of the

white s o l i d was now i d e n t i c a l to that obtained from reaction i n t e t r a -

hydrofuran i . e . strongly resembling the i . r . spectrum of Ph2CNH2Br. Analysis

indicated the absence of sulphur i n t h i s solid which was not investigated

further.

Tetrathiotetraimide and Benzoyl Chloride

Benzoyl chloride (1.5 ml., 13 m.mole) was added to t e t r a t h i o t e t r a -

imide (0.5 g., 2.65 m.mole) under ether (20 ml.) at -196°. The s t i r r e d

suspension was allowed to reach room temperature. After 1^ hours no

apparent change had taken place, so pyridine ( l ml., 12.4 m.mole) was

added as an acid scavenger. Within 30 minutes the ether was pale yellow

and did not change during a further 4-̂ hours. The suspension was f i l t e r e d

to give a white solid (A) and a yellow f i l t r a t e . Evaporation of the

f i l t r a t e under reduced pressure gave a small quantity of yellow solid and

- 38

yellow o i l which were not inuestigated further. The i . r . spectrum of the

white s o l i d (A) indicated unreacted tetrathiotetraimide.

Tetrathiotetraimide and Hydrogen Chloride

Hydrogen chloride, dried by passage through a long P̂ Ô tube, was

passed i n t o tetrathiotetraimide (0.45 g., 2.39 m.mole) suspended i n

chloroform (20 ml.). The chloroform turned yellow and the colour i n -

t e n s i f i e d to orange within 40 minutes. The suspension was f i l t e r e d to

giue a pale solid (A) and a red solution. Euaporation of the f i l t r a t e

under reduced pressure gaue a uery small quantity of yellow orange crystals

and a dark brown s o l i d . The l a t t e r was not inuestigated further. The

yellow orange crystals were i d e n t i f i e d as t h i o t r i t h i a z y l chloride by

i . r . spectrum. The white insoluble s o l i d (A) was sim i l a r l y i d e n t i f i e d as

a mixture of ammonium chloride and unreacted tetrathiotetraimide.

Tetrathiotetraimide and Chlorine

Chlorine was bubbled through a suspension of tetrathiotetraimide

(l.O g.) i n carbon tetrachloride (60 ml.) at 20°. Heat was euolued and

the suspension immediately turned orange-brown. As the reaction proceeded

the solution became clearer and paler. After no further colour change,

the suspension was f i l t e r e d ; the insoluble off-white solid (mostly ammonium

chloride) was discarded. The f i l t r a t e was euaporated under reduced pressure

to giuB golden yellow crystals, which were recrystallised from carbon t e t r a -

chloride (0.53 g., 30 ̂ based on (SNH)^). Melting point (77°) and i . r .

spectrum were the same as for (NSCl)^ prepared from tetrasulphur t e t r a -

- 39 -

79 n i t r i d e or t h i o d i t h i a z y l dichloride and chlorine. • Tetrathiotetraimide and Sulphuryl Chloride

Sulphuryl chloride (5 ml., B.35 g., 60 m.mole) was added to te t r a -

thiotetraimide (1.5 g.,.8 m.mole) and carbon tetrachloride (30 ml.) at

-196°, and the s t i r r e d mixture warmed to 20°. The suspension quickly

darkened and gas was evolved. After no further colour change (2 hours)

the clear orange-red solution was separated from pale pink so l i d (ammonium

chloride), evaporated under reduced pressure and the residue recrystallised

from carbon tetrachloride to give yellow crystals (0.9 g., 35 ̂ based on

(SNH).). (Found: N,17.6; 3,39.0. (NSCl) requires N,17.2; 3,39.3).

The i . r . spectrum was the same as that of the previous product.

Tetrathiotetraimide and Tetrachloroethylene

Tetrathiotetraimide (0.5 g., 2.65 m.mole) was refluxed with t e t r a -

chloroethylene (20 ml., 195.7 m.mole) for 3 hours. At f i r s t a creamy

flocculent suspension formed, the colour of the tetrachloroethylene changing

to orange then red during the reaction. The solution was allowed to reach

room temperature (20°) and was then f i l t e r e d . Some orange needles (A)

remained on the sinter and the f i l t r a t e on evaporation under reduced pressure

yielded an orange-yellow solid (B). Both solids (A) and (8) were i d e n t i f i e d

by i . r . spectrum as tetrasulphur t e t r a n i t r i d e . No trace of absorptions 1 80

due to C-Cl (850-550 cm' )" could be found and the reaction was not

studied fu r t h e r .

40

SECTION I I I

ORGANOMETALLICS

T e t r a t h i o t e t r a i n i i d s and Trimethylaluminiufn

Trimethylaluminium ( 1 ml., 10.4 m.mole) was added t o t e t r a t h i o -

t e t r a i m i d e (0.94 g., 5 m.mole) under toluene (30 ml.) at -196°. On

warming t o room temperature (20°) w i t h s t i r r i n g , methane, i d e n t i f i e d by

i . r . spectrum was euolued and a clear orange s o l u t i o n formed. A f t e r 2

hours an orange-yellow s o l i d p r e c i p i t a t e d and the suspension was f i l t e r e d

a f t e r a f u r t h e r 1 hour. Hexane (30 ml.) was added to the f i l t r a t e pre-

c i p i t a t i n g more orange-yellow s o l i d and the solvent decanted. The i . r .

spectrum of the orange-yellow s o l i d included absorptions i n both the 1 7 1 9

NH (3300-3200 cm ) and SIM (580-930 cm ) s t r e t c h i n g regions.

(Found: C,25.05; H,3.24; S,43.6). I t was concluded t h a t s u b s t i t u t i o n

was incomplete and the r e a c t i o n was not i n v e s t i g a t e d f u r t h e r .

T e t r a t h i o t e t r a i m i d e and n-Butyl Lithium

A s o l u t i o n (2.33m, 2.0 ml., 4.66 m.mole) of n-butyl l i t h i u m i n

hexane was added t o t e t r a t h i o t e t r a i m i d e (0.19 g., 1.0 m.mole) i n t e t r a -

hydrofuran (4.5 ml.) a t -196° i n a tube f i t t e d w i th a break seal and con-

s t r i c t i o n . Uhen the hexane had s o l i d i f i e d , the tube was evacuated, sealed

a t the c o n s t r i c t i o n and allowed to stand (20°, 90 hours); the colour

g r a d u a l l y changed from pale yellow t o red, then t o yellow, blue and

yellow. The tube was opened to a vacuum l i n e v i a the break-seal and the

41

v/olume of butane euolued was measured (3.7 m.mole) using a THpler

pump. The yellow i n s o l u b l e s o l i d uas presumed t o be predominantly

(SWLi)^.

T e t r a t h i o t e t r a i m i d o l i t h i u m and Plethyl Iodide

n e t h y l i o d i d e ( l ml., 2.3 g., 15 m.mole) was added t o a cooled

(-196°) mixture of (SNLi)^ and n-hexane, prepared as aboue from t e t r a -

t h i o t e t r a i m i d e (0.47 g., 2.5 m.mole) and n-b u t y l l i t h i u m (10 m.mole) i n

hexane. An orange suspension formed on warming to room temperature which

turned yellow i n 2 hours. The suspension was f i l t e r e d and the f i l t r a t e

evaporated under reduced pressure to y i e l d a red t a r which was not studied

f u r t h e r .

T e t r a t h i o t e t r a i m i d o l i t h i u m and T r i m e t h y l c h l o r o s i l a n e

T r i m e t h y l c h l o r o s i l a n e (3 ml., 21.6 m.mole) was added t o (SNLi)^,

prepared from t e t r a t h i o t e t r a i m i d e (0.94 g., 5 m.mole) and n-butyl l i t h i u m

(21 m.mole), i n hexane at -196°. The s t i r r e d mixture was allowed t o warm

to room temperature 20°, forming a deep red s o l u t i o n . A f t e r 3 hours the

s o l u t i o n clouded and a f t e r 48 hours hexane (6 ml.) was added to p r e c i p i t a t e

l i t h i u m c h l o r i d e . The suspension was f i l t e r e d and the f i l t r a t e evaporated

under reduced pressure t o giue an orange semi-solid which was dissolwed

i n benzene, f i l t e r e d , and the benzene removed by evaporation under reduced

pressure to y i e l d a deep red, purgent smelling l i q u i d . Analysis and i . r .

spectrum i n d i c a t e d t h a t t h i s l i q u i d was probably mostly the t e t r a t r i m e t h y l -

»4-s i l y l d e r i v a t i v e of (SNH),. I . r . spectrum absorptions at (cm •*•); 2959s,

42

2933sh, 2857m, 1460w, 1408w, 1379w, 1250s, 1185m, 1093w, e77sh, 844s,

796w, 757m, 690w, 633w. 77 • -1 T r i m e t h y l c h l o r o s i l a n e ' ' shows i . r . absorptions at (cm ) ; 2977s, 2912m,

1454w, 1260s, 857s, 767m, 700w, 640m, 487m. (Found: C,30.5; H,5.36.

Required f o r (SI\lSi(CH2)3)4: C,30.3; H,7.56).

T e t r a t h i o t e t r a i m i d o l i t h i u m and Acetyl Bromide

Acetyl bromide (1.5 ml., 21 m.mole) was added to (SNLi)^, prepared

from t e t r a t h i o t e t r a i m i d e (0.5 g., 2.65 m.mole) a s l i g h t excess of n-butyl

l i t h i u m (15 m.mole), i n THF/hexane at -70°. The yellow suspension became

• a dark red s o l u t i o n and some gas was evolved as reactants warmed to room

temperature (20°). A f t e r 4 hours i n a low temperature bath (-100°)

a l i t t l e l i g h t coloured p r e c i p i t a t e had formed which was f i l t e r e d o f f .

A f t e r removing 80^ of the solvent by evaporation under reduced pressure

hexane (lO ml.) was added, but no s o l i d was p r e c i p i t a t e d . Continued

evaporation under reduced pressure gave an o i l y red l i q u i d , i n s o l u b l e i n

both ether and heptane, and f i n a l l y a red t a r which was not i n v e s t i g a t e d

f u r t h e r .

T e t r a t h i o t e t r a i m i d o l i t h i u m and lodobenzene

lodobenzene (2.9 ml., 26 m.mole) was added to (SNLi)^ (prepared from

(SNH)^ (0.94 g., 5 m.mole) and n-butyl l i t h i u m (21,3 m.mole) i n THF/hexane)

at 2G°C, The yellow suspension darkened to a medium brown which did not

change during 96 hours s t i r r i n g a t 20°. The suspension was f i l t e r e d t o

give a pale brown s o l i d and dark red/brown f i l t r a t e . The f i l t r a t e was

43 -

evaporated under reduced pressure y i e l d i n g a red t a r which was not

i n v e s t i g a t e d f u r t h e r .

T e t r a t h i o t e t r a i m i d o l i t h i u m and Chlorine

Chlorine was bubbled i n t o (SWLi)^ (prepared from (SI\IH)^ (0.94 g.,

5 m.mole) and n-b u t y l l i t h i u m (21 m.mole) i n THP/hexane) suspended i n

carbon t e t r a c h l o r i d e (40 ml.) a t -23°. A f t e r 5 minutes vigorous r e a c t i o n

the suspension was f i l t e r e d t o give a white s o l i d and yellow f i l t r a t e .

Evaporation of the f i l t r a t e under reduced pressure gave a red t a r which

was not i n v e s t i g a t e d f u r t h e r .

- 44 -

SECTION lU

OXYGEN COMPOUNDS

T e t r a t h i o t e t r a i m i d e and Acetic Anhydride

Acetic anhydride (1.5 ml., 16 m.mole) was added to t e t r a t h i o t e t r a i m i d e

(0.5 g., 2.65 m.mole) under ether at 20° and s t i r r e d f o r 2 hours. There

being no v i s i b l e sign of r e a c t i o n the ether was removed by evaporation

under reduced pressure and more a c e t i c anhydride ( l 5 ml., 160 m.mole) was

added. The reactants were heated at 125° under r e f l u x u n t i l , a f t e r 75

minutes a c l e a r dark red s o l u t i o n formed. The s o l u t i o n was f i l t e r e d and

evaporated under reduced pressure to give an orange s o l i d . A red semi-

s o l i d c o l l e c t e d i n the cold t r a p . The i . r . spectrum of the orange s o l i d

i n d i c a t e d t e t r a s u l p h u r t e t r a n i t r i d e and the re a c t i o n was not i n v e s t i g a t e d

f u r t h e r .

T e t r a t h i o t e t r a i m i d e and Ethylene Oxide

Ethylene oxide (lO ml., 200 m.mole) was added to t e t r a t h i o t e t r a i m i d e

(0.94 g., 5 m.mole) a t -78°. On warming to 0°C the l i q u i d turned f a i n t l y

yellow and showed no f u r t h e r change a f t e r 150 hours at low temperatures

(between -30° and-46°). The suspension was f i l t e r e d leaving a white s o l i d

on the s i n t e r , i d e n t i f i e d by i . r . spectrum as t e t r a t h i o t e t r a i m i d e . The

yellow f i l t r a t e was evaporated under reduced pressure to y i e l d a white

s o l i d , i d e n t i f i e d by i . r . spectrum as t e t r a t h i o t e t r a i m i d e .

45

T e t r a t h i o t e t r a i m i d e and Epichlorohydrin

Epichlorohydrin (7 ml. 90 m.mole) was s t i r r e d w i t h t e t r a t h i o t e t r a i m i d e

(0.15 g., 0.80 m.mole) f o r 1 hour w i t h no apparent r e a c t i o n . On heating to

r e f l u x (120°) the s o l i d dissolved and gave an orange s o l u t i o n . A f t e r 1

hour the s o l u t i o n was allowed to cool to room temperature (20°) a white

s o l i d c r y s t a l l i s i n g out. The s o l i d was f i l t e r e d o f f , washed with ether

and i d e n t i f i e d by i . r . spectrum as t e t r a t h i o t e t r a i m i d e . Evaporation of

the f i l t r a t e under reduced pressure y i e l d e d a t a r r y s o l i d which would not

m u l l .

The r e a c t i o n was repeated, r e f l u x i n g f o r 48 hours. The r e s u l t i n g

dark s o l u t i o n y i e l d e d a dark t a r which was not i n v e s t i g a t e d f u r t h e r .

46

DISCUSSION

1. METAL HALIDES

19

Following the procedure of Goehring e t . a l . reactions were attempted

between (SNH)^ and manganese ( l l ) , and i r o n ( l l ) , c h l o r i d e s . In the f i r s t

case examination of the i . r . spectrum of the product showed no sign of

SN absorption, and i n the second case the product i s o l a t e d did not contain

sulphur. These reactions were not studied f u r t h e r .

Reaction between (SNH)^ and the strong Lewis acids AlBr^, '^ICl^ and

SnBr^ gave products of two types. The aluminium halides gave amorphous

s o l i d s analysing as the 1:1 adducts (SNH)^.AlBr2 (orange) and (SI\IH)^.AlCl2

(pale orange-yellow). The near i . r . spectra of these compounds were closely

s i m i l a r t o t h a t of the parent imide ( i . e . NH absorptions at 3330 - 3170 cm

and SN s t r e t c h i n g frequency at 825 cm"'''), and so they are probably o'adducts v i a donor n i t r o g e n as i n the Ŝ N̂ adducts of boron t r i f l u o r i d e and antimony

81

pen t a c h l o r i d e . With t i n tetrabromide the only i n s o l u b l e (and major) pro-

duct was a dark red s o l i d whose i . r . spectrum was i d e n t i c a l t o t h a t of 17

2S^N^.SnBr^ (prepared from Ŝ N̂ and SnBr^ i n hexane ) contaminated with a

l i t t l e NH^Br. No f u r t h e r work was c a r r i e d out on t h i s r e a c t i o n .

47

2, OTHER HALIDES

Tr i m e t h y l c h l o r o s i l a n e

In attempting to make d e r i v a t i v e s of the type (SNX)^ t e t r a t h i o t e t r a i m i d e

was t r e a t e d w i t h t r i m e t h y l c h l o r o s i l a n e . The two substances did not react

when heated under r e f l u x f o r 9 hours; so the re a c t i o n was repeated i n

p y r i d i n e (which would act as a dehydrohalogenating agent). A f t e r r e f l u x i n g

f o r 1 hour a white s o l i d was f i l t e r e d o f f and the f i l t r a t e evaporated under

reduced pressure to give a red brown residue. The i , r , spectra of the two

s o l i d s obtained from t h i s r e a c t i o n showed no trace of t r i m e t h y l s i l y l peaks.

The spectrum of the red brown s o l i d i n d i c a t e d the presence of Ŝ N̂ ; and the

i . r . spectrum of the white s o l i d was i d e n t i c a l t o t h a t of p y r i d i n e hydro-78

c h l o r i d e . Although t h i s r e a c t i o n was not studied further,, i t i s suggested

t h a t R„Si d e r i v a t i v e s could perhaps be prepared under milder conditions (e.g.

lower temperature and/or shorter r e a c t i o n t i m e ) .

Acetyl Chloride

Garcia-Fernandez reported an a c e t y l d e r i v a t i v e of (SNH)^ prepared

by r e a c t i n g (SNH)^ w i t h a c e t y l c h l o r i d e i n e t h y l acetate containing a trace

of potassium carbonate. This work was repeated but the only products i s o l a t e d

were t e t r a t h i o t e t r a i m i d e and t e t r a s u l p h u r t e t r a n i t r i d e ( i d e n t i f i e d from t h e i r

i . r . s p e c t r a ) . This matter has already been discussed i n the I n t r o d u c t i o n

(see p. 4- )> the explanation o f f e r e d i s t h a t t h i s report has entered the 13

l i t e r a t u r e through a m i s t r a n s l a t i o n of work reported by Arnold. Refluxing

48

z o

\m OJ

00̂

-.9.

in

.3̂

49

a c e t y l c h l o r i d e and (SI\1H)^ d i d however react. A yellow s o l i d was obtained

which was i d e n t i f i e d by i . r . spectrum and analysis as a 1:1 mixture of

S^N^Cl and NH^Cl. T h i o t r i t h i a z y l c h l o r i d e S^N^'^Cl" i s a w e l l established

compound, the s t r u c t u r e of the Ŝ N̂ ^ c a t i o n having been determined by X-ray 82 83

d i f f r a c t i o n studies as a nearly planar seven-membered r i n g . '

Ac e t y l Bromide

S i m i l a r l y (SNH)^ and a c e t y l bromide reacted at room temperature (20°)

to give a yellow s o l i d characterised by analysis and i . r , spectrum as a 1:1

mixture of t h i o t r i t h i a z y l and ammonium bromides, 98% formic.acid was found

to be much more e f f i c i e n t than water at washing out the ammonium s a l t .

Unlike S^N^Cl which i s r a p i d l y hydrolysed by atmospheric moisture (golden 84

yellow c r y s t a l s t u r n black) , S^N^Br i s a i r s t a b l e . This may be due to

the s t a b i l i s i n g e f f e c t of the l a r g e r Br" ( i . e . l e s s repulsive i n t e r a c t i o n

between neighbouring S^Mj^ ions i n the c r y s t a l l a t t i c e ) .

On account of the complexity of some of the reactions of (SNH)^ with

halides i t was decided t o i n v e s t i g a t e the behaviour of the imide w i t h the

simplest possible halogen compounds, i . e . the halogens themselves.

Bromine

Analysis and the i . r . spectrum of the yellow s o l i d obtained from the

r e a c t i o n w i t h bromine ( i n CCl^) i n d i c a t e d a 1:1 mixture of t h i o t r i t h i a z y l

and ammonium bromides. (The l a t t e r could again be removed by washing w i t h

98^ formic a c i d ) . This r e a c t i o n can be explained according to the equation:

- 50 -

S^N^Br + NH^Br

Such a simple equation i s not possible f o r the reactions with the a c e t y l

h a l i d e s . One possible equation would be:

W A ^ 2CH3C0Br S^N3Br + NH^Br + (CH3C0)2

Unfortunately no trace of d i a c e t y l could be found when the v o l a t i l e products

of the r e a c t i o n were examined by vapour phase chromatography. The r e t e n t i o n

times, expressed as distances on the recording chart a f t e r i n j e c t i o n of the

sample, compared w i t h those of known pure compounds, are given below.

Retention Time Source cm.

6.05 Di a c e t y l 6.4 Acetyl bromide 7.6 Unknown 8.7 Acetic acid

More work i s necessary to discover the i d e n t i t y of the substance g i v i n g

a r e t e n t i o n time corresponding t o 7.6 cm. (e.g. mass spectra a f t e r chromato-

graphic s e p a r a t i o n ) .

As the r e a c t i o n between (SNH)^ and bromine, g i v i n g S^N^Br and NH^Br,

could be expressed by a simple equation i t was decided t o i n v e s t i g a t e reactions

between (SNH)^ and other compounds of type X-Br. Ŝ N̂ s a l t s can be formed

i n two ways:

- 51 -

( i ) Ŝ N̂ Ĥ + XBr a. S^N3X + NH^Br

( i i ) Ŝ N̂ Ĥ + XBr * S^N3Br + NĤ X

Since there i s no evidence t o date f o r a predominantly covalent t h i o t r i t h i a z y l

compound, the formation of a stable S^N3X s a l t according to ( i ) , would be , 85

favoured by a la r g e group X w i t h high e l e c t r o n e g a t i v i t y ( c f . SO3F, SO3CI

N(S02C1)2 s a l t s ^ ^ ) . P a i r i n g of NH^^ wi t h the smaller anion (Br ) also

maximises the l a t t i c e energy of the ammonium s a l t .

N-Bromosuccinimide and N-bromodiphenylketimine were selected as two

s u i t a b l e " a c t i v e N-halogen compounds."

N-Bromosuccinimide

T e t r a t h i o t e t r a i m i d e and N-bromosuccinimide ( l : l molar r a t i o ) reacted

r a p i d l y i n THF to give a yellow suspension. The yellow s o l i d was f i l t e r e d

o f f and the f i l t r a t e evaporated under reduced pressure to give a dark brown

residue which was ext r a c t e d w i t h ether. Tetrasulphur t e t r a n i t r i d e and

succinimide ( i n s o l u b l e ) were obtained on r e c r y s t a l l i s a t i o n of the e x t r a c t

from hexane (both compounds i d e n t i f i e d from i . r , s p e c t r a ) . The yellow s o l i d

was s i m i l a r l y i d e n t i f i e d as a mixture of ammonium and t h i o t r i t h i a z y l bromides.

Apparently e l i m i n a t i o n of hydrogen bromide had occurred between (SNH)^ and

N-bromosuccinimide t o give S^N^, HBr and succinimide, perhaps according t o

the equation:

(SNH)^ + 2C^H^02NBr Ŝ N̂ + 2HBr + 2C^H^02l\lH

( I t does however seem u n l i k e l y t h a t such a simple equation could accurately

express the undoubtedly complex nature of t h i s r e a c t i o n . ) The production

52

of some S^N^Br and NH^Br i s s i m i l a r l y d i f f i c u l t t o explain (unless there

was some simultaneous formation of disuccinimide (C^H^02N)2). When the

re a c t i o n was repeated using t e t r a t h i o t e t r a i m i d e and N-bromosuccinimide i n

a molar r a t i o 1:2 a yellow suspension was again produced. A yellow s o l i d

was f i l t e r e d o f f and the f i l t r a t e on evaporation under reduced pressure

y i e l d e d a small q u a n t i t y of dark brown residue. This residue was extracted

w i t h ether, and the e x t r a c t r e c r y s t a l l i s e d from hexane to give Ŝ N̂ ( i d e n t i f i e d

from i t s i . r . spectrum). The i n s o l u b l e yellow s o l i d , the major product, was

i d e n t i f i e d from i t s i . r . spectrum as a mixture of t h i o t r i t h i a z y l and

ammonium bromides. Some e l i m i n a t i o n of HBr (formation of S^N^) had obviously

taken place, but the major r e a c t i o n seems to be s i m i l a r to the reaction of

(S(\IH)^ w i t h a c e t y l bromide i . e . r i n g c o n t r a c t i o n t o S^N^Br and formation of

WH^Br.

N-Bromodiphenylketimine

T e t r a t h i o t e t r a i m i d e and N-bromodiphenylketimine ( i n 1:1 molar r a t i o )

reacted r a p i d l y i n THF, (as di d (SNH)^ and N-bromosuccinimide) to give a

yellow suspension. A f t e r 20 minutes at 20° the mixture was f i l t e r e d to give

a white s o l i d . The red/green f i l t r a t e on evaporation under reduced pressure

gave a red residue which would not mull and was not i n v e s t i g a t e d f u r t h e r .

Examination of the i . r . spectrum of the white s o l i d revealed peaks character-

i s t i c of (SNH)^ and, w i t h one change i n i n t e n s i t y of absorption at 15.64^, of

diphenylketimine hydrobromide. There were no absorptions due to NĤ"*", so

rea c t i o n s of types ( i ) and ( i i ) could be discounted. Since N-bromodiphenyl-

53 -

ketimine has a tendency t o deprotonate THF, to give diphenylketimine 87

hydrobromide, i t was decided t o repeat the r e a c t i o n i n another solvent.

Keeping the molar r a t i o 1:1 the re a c t i o n was repeated i n toluene,

s t i r r i n g a s o l u t i o n of N-bromodiphenylketimine with a suspension of (SNH)^.

The r e a c t i o n was n a t u r a l l y much slower under these conditions, and a f t e r

two hours the mixture was f i l t e r e d t o give a white s o l i d and red f i l t r a t e .

Evaporation of the f i l t r a t e under reduced pressure yielded yellow c r y s t a l l i n e

S^N^ ( i d e n t i f i e d from i . r . spectrum). The i . r . spectrum of the white s o l i d

was i d e n t i c a l to t h a t of the white s o l i d obtained from the re a c t i o n i n THF,

save t h a t those peaks corresponding to (SNH)^ were much stronger. (This

was t o be expected since the (SNH)^ was not i n s o l u t i o n i n i t i a l l y and

r e a c t i o n would proceed more slowly.) Washing w i t h THF removed both (SNH)^

and S^N^, (detected by examination of i . r . s p e c t r a ) . The i . r . spectrum of

the residue was i d e n t i c a l t o t h a t of the white s o l i d obtained from the

i n i t i a l r e a c t i o n i n THF, i . e . the spectrum d i f f e r e d from t h a t of Ph2CNH2Br

i n one respect only, change i n i n t e n s i t y of the peak at 15.64^. Apparently

Ph2CNBr had deprotonated t e t r a t h i o t e t r a i m i d e forming Ph2CNH2Br and Ŝ N̂

(a s i m i l a r deprotonation i s observed when diphenylphosphine reacts with 88

Me2NCl t o give tetraphenyldiphosphine and Me2NH2Cl. ) . As t h i s r e a c t i o n

gave no new compound i t was not studied f u r t h e r .

Before going on t o discuss the re a c t i o n of t e t r a t h i o t e t r a i m i d e and

c h l o r i n e (as mentioned e a r l i e r page 4S ) i t i s convenient to mention here

two f u r t h e r r e a c t i o n s ; those of (SNH)^ with benzoyl c h l o r i d e and hydrogen

c h l o r i d e .

54

Benzoyl Chloride '

Because a c e t y l c h l o r i d e reacted with (SNH)^ i t was decided to i n v e s t i -

gate the analogous r e a c t i o n w i t h benzoyl c h l o r i d e . Benzoyl c h l o r i d e was

s t i r r e d w i t h an ether suspension of t e t r a t h i o t e t r a i m i d e f o r 1 ^ hours, no

apparent change t a k i n g place. Pyridine was then added, ( t o act as a

dehydrohalogenating agent) and the ether turned yellow w i t h i n 30 minutes.

A f t e r a f u r t h e r 4-| hours, the mixture was f i l t e r e d to give a white s o l i d

which was i d e n t i f i e d from i t s i . r . spectrum as unreacted (SI\IH)^, and a

yellow f i l t r a t e . Evaporation of the f i l t r a t e under reduced pressure gave

a small q u a n t i t y of yellow s o l i d and yellow o i l which were not studied

f u r t h e r . In view of the lesser r e a c t i v i t y of benzoyl c h l o r i d e towards 89

" a c t i v e hydrogen atoms", as compared w i t h a c e t y l c h l o r i d e , more vigorous

c o n d i t i o n s should perhaps be chosen (e.g. r e f l u x i n g f o r several hours) i n

any f u t u r e re-examination of t h i s r e a c t i o n . Addition of p y r i d i n e to the

r e a c t i o n mixture was c a r r i e d out to create conditions analogous to those

normally employed i n the Schotten-Baumann r e a c t i o n f o r benzoylation of an

"a c t i v e hydrogen" containing compound.

Hydrogen Chloride

Hydrogen c h l o r i d e , d r i e d by passage through a long P^O^^ tube, was

passed i n t o a suspension of (SNH)^ i n chloroform. A f t e r 40 minutes the

mixture was f i l t e r e d l e aving a white s o l i d on the f i l t e r . The i . r . spectrum

of t h i s m a t e r i a l i n d i c a t e d a mixture of NH^Cl and unreacted (SNH)^.

Evaporation of the f i l t r a t e

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